关于stm32定时器的理解
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
表面意思是输出控制极性为高，但是意思是定时器输入0，不反相，输出0;
输出控制极性为低，定时器输入0，反相输出1;
CC1E控制开关。
#define TIM_OCPolarity_High ((uint16_t)0x0000)
#define TIM_OCPolarity_Low ((uint16_t)0x0002)
定时器通道写法: TIM_OC2 意思是定时器channel 2 ，TIM_OC1意思是定时器通道1.
//小波Linux
pwm占空比:
TIM_SetCompare1(TIM2,led1pwmval);
TIM_SetCompare2(TIM3,led0pwmval);
TIMX为哪个定时器，ledxpwmval为占空比的值;
TIM2_PWM_Init(899,0); //不分频 72000/900=8Khz
arr 自动重装载计数器初值 900 =899+1;
占空比例如 占 50% = 450 / 900
ledxpwmval = 450;
定时器初始化，里面有个重映射
void TIM2_PWM_Init(u16 arr,u16 psc) {
GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); //使能定时器3时钟 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE); //使能GPIO外设和AFIO复用功能模块时钟 //设置该引脚为复用输出功能,输出TIM2 CH1的PWM脉冲波形 PA0 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0; //TIM_CH1 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIO //初始化TIM2 TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值 TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式 TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位 //初始化TIM2 Channel 1 PWM模式 TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2 TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能 TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高 TIM_OC1Init(TIM2, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM2 OC1
TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable); //使能TIM2在CCR1上的预装载寄存器 TIM_Cmd(TIM2, ENABLE); //使能TIM2
//TIM3 PWM部分初始化 //PWM输出初始化 //arr:自动重装值 //psc:时钟预分频数 void TIM3_PWM_Init(u16 arr,u16 psc) { GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure; RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //使能定时器3时钟 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB " RCC_APB2Periph_AFIO, ENABLE); //使能GPIO外设和AFIO复用功能模块时钟 GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射 TIM3_CH2->PB5 //设置该引脚为复用输出功能,输出TIM3 CH2的PWM脉冲波形 GPIOB.5 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //TIM_CH2 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIO //初始化TIM3 TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值 TIM_TimeBaseStructure.TIM_Prescaler =psc; //设置用来作为TIMx时钟频率除数的预分频值 TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上计数模式 TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位 //初始化TIM3 Channel2 PWM模式 TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //选择定时器模式:TIM脉冲宽度调制模式2 TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比较输出使能 TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出极性:TIM输出比较极性高 TIM_OC2Init(TIM3, &TIM_OCInitStructure); //根据T指定的参数初始化外设TIM3 OC2
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIM3在CCR2上的预装载寄存器 TIM_Cmd(TIM3, ENABLE); //使能TIM3
关键字:STM32 定时器
编辑:什么鱼 引用地址:http://www.eeworld.com.cn/mcu/article_2016121632390.html
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